The Mars Exploration Rover mission logged another textbook-rewriting month in October 2009 with more discoveries of geologic gems, new robot achievements balanced with equal amounts of challenges and frustrations overcome, topped off with special honors.

I wonder if this came from the same original body as Block Island, or if Meridiani is the kind of slowly deflating landscape that accumulates meteorites at its surface, like the ANSMET meteorite hunting spots in Antarctica?

From notable achievements and new discoveries to trials and tribulations and harbingers of hope, the Mars Exploration Rovers seemed to experience the gamut on the Red Planet this September, their 69th month on an expedition that originally set out back in 2004 for a three-month tour.

The Mars Exploration Rovers hunkered down in place in August and delivered more mission "gold" as they achieved new milestones and uncovered more scientific gems, not the least of which was a blockbuster of a meteorite. But August proved to be a stormy month, uniquely challenging and one that many on the Mars Exploration Team will never forget.

The Mars Exploration Rovers maintained a busy schedule in July: Spirit worked day and night doing whatever it could to make use of its abundant energy; Opportunity effectively treated its “hot” right front wheel and got back to making some consecutive long drives toward the still distant Endeavour Crater.

It's been a relatively quiet but scientifically significant month on the Red Planet for the Mars Exploration Rovers. While Opportunity continued its long journey to Endeavour Crater, forced to take it slower and make longer stops to rest its 'hot' front wheel, Spirit, seemingly just biding its time embedded in a sand pit it slipped into in April, turned up one of the most intriguing discoveries on the mission to date.

The Mars Exploration Rovers hit some rough patches in May as Spirit sat stuck in a sand patch all month and Opportunity had to stop again to rest its right front wheel but with a little help from Mars, the intrepid, twin robot field geologists cruised through the summer solstice with the energy and invincibility of a couple of teenage robots.

The Mars Exploration Rovers challenged their ground crews with an April full of high drama, a little suspense, and a lot of energy. While Spirit lived through a kind of robot soap opera, complete with bewildering reboots and bouts of amnesia, Opportunity roved forward and back into the fast lane on a restored front wheel, slowing down for a brief visit to a series of small, intriguing craters and an unplanned close encounter with a pesky little purgatoid.

The Mars Exploration Rovers logged a memorable March, with Spirit finally making some serious tracks and setting a new driving record for a five-wheeled rover, and Opportunity getting a first glimpse on the distant horizon of its next big attraction, Endeavour Crater as it crossed a geologic boundary into a new field of "blueberries."

Despite some struggles with terrain and technology, the Mars Exploration Rovers moved their missions forward in February, as Spirit and Opportunity pressed on toward their next major Martian attractions.

The Mars Exploration Rover mission crossed the finish line of another major milestone this month, marking its fifth anniversary of exploring the Red Planet. As team members celebrated and shared stories in events all around Los Angeles, Spirit and Opportunity kept on roving, bucking up under the inevitable pains of growing older. They're heading now for their next major destinations.